1. Field of the Invention
The present invention relates to a method of preparing a hole for slant drilling, including the provision of pre-milled windows which can be oriented to any direction to provide an outlet for penetrating the earth at various depths along the casing string.
2. Description of the Prior Art
Well packers utilized for isolating a zone in a well below the packer from a zone above the packer for performing a well service operation such as perforating, formation, fracturing, or pressure containment are known. Further, it is known to use wireline apparatus to initially run a packer downhole to a selected position and to set the packer. After the packer has been set, the wireline is removed from the well and a tubing string is run down the well and attached to such packers for performing the well operations. The packer can then be remove from the well by manipulation of the tubing string and by shearing pins, one-direction setting devices, or other means, freeing the packer from the well casing and pulling the tubing string and packer out of the well as a unit. The packer can then be redressed and used again in the same well or used later at a different location.
It is also known to insert a whipstock into a well casing to provide a angled surface for directing a drill or similar tool outward from the centerline of the well towards a wall to drill through the casing wall and into the earth to tap a natural gas deposit at a particular depth.
It has not been possible prior to this invention to provide a pre-milled window in the casing in conjunction with an orientation device, which, when used in combination with the whipstock, allow a drill to be inserted and aligned with the window such that the drill can be manipulated through the window to contact the surrounding earth directly without having to drill through the casing.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.